In recent years, organic electroluminescence display panels in which organic electroluminescence elements are disposed on a substrate. The organic electroluminescence display panel (hereinafter, organic EL display panel) achieves high visibility through the use of auto-luminous organic EL elements, and is also highly shock-resistant given that the elements are completely solid units. Each of the organic EL elements is a current-driven light-emitting diode configured such that an organic light-emitting layer or similar employs the phenomenon of organic material electroluminescence to produce light by recombination of carriers between a pair of electrodes, namely an anode (e.g., a pixel electrode) and a cathode (e.g., a common electrode).
Among organic EL display panels, top-emission panels, in which light is emitted from the cathode side, are the focus of attention in terms of attempts to improve the brilliance by making effective use of the light emitted from the organic light-emitting layer. In such a organic EL display panel, the cathode is a transparent electrode material such as indium tin oxide or indium zinc oxide spread over the entirety of the surface area. However, the transparent electrode material is highly resistive relative to metals. As such, a problem arises in that decreasing voltage toward the centre of the display area causes a decrease in current supplied to the organic EL elements, and in turn leads to degradation in display quality. An organic EL display panel has been proposed in which the organic EL elements are disposed between the cathode and a power supply layer connected thereto (see, for example, Patent Literature 1 and 2). Here, the power supply layer is a term designating a low-resistance wire supplying power from a power supply to the cathode, also termed an auxiliary wire.
FIG. 17 is a partial cross-sectional diagram illustrating a sample configuration of an organic EL display panel 90 having a power supply layer. A hole injection layer 904 is formed so as to cover a pixel electrode 902 and a power supply layer 903, which are formed with separation over a substrate 901. The power supply layer 903 and the hole injection layer 904 serve as the power supply layer. A resin partition layer 905 having apertures over each of the pixel electrode 902 and the power supply layer 903 is provided over the power supply layer. An organic light-emitting layer 906 is formed in the apertures over the pixel electrode 902. A functional layer 907 and a common electrode 908 are then sequentially layered thereon.
The functional layer 907 is provided with the aim of encouraging electron injection from the common electrode 908 to the organic light-emitting layer 906. Known materials used for the functional layer 907 is, for example, an organic material with electron injection capabilities mixed with an alkali metal or with an alkali earth metal.